There are three specific aims of this project. The first is to examine 12-0-tetradecanoyl-phorbol-13-acetate (TPA) treated leukemic cells for changes in surface antigen profile and proliferative capacity. Cells will be freshly obtained from patients with ANLL, ALL, AUL, CLL, CML in blast crisis and hairy cell leukemia. They will be tested for ability to bind a number of monoclonal and conventionally derived antibodies to establish a baseline antigen "profile", then allowed to incubate with TPA and retested. Their proliferative capacity will be tested before and after incubation as well. The Ortho Spectrum III Cytofluorograf will be used for all analyses. We will determine whether TPA treatment is helpful in inducing maturation in vitro, classifying previously unclassifiable cells, and decreasing leukemic cell proliferation. Second, we will determine whether precursors of granulocyte and monocyte colonies (CFU-G/M) can be induced to proliferate by one stimulus and directed towards granulocyte or monocyte differentiation by another. Cells will be grown in semisolid agar culture which will contain compounds known to inhibit monocyte colony development. TPA will be added late in incubation to attempt to induce cells in developing colonies to become monocytes. This will establish whether a reserve pool of immediate precursors to granulocytes and monocytes is likely to exist in vivo. Third, we will assess whether activated helper T cells combined with monocytes in liquid culture can produce colony stimulating activity(CSA). We will combine populations of monocyte subsets and T cell subsets purified by adherence procedures, E rosetting and cell sorting in the FACS IV. We will then assess the ability of each cell combination to produce CSA. We will test both cells from normal donors and from patients with neutropenia or monocytosis. We suspect that defects in the helper T cell-monocyte interaction in vivo may lead to inadequate CSA production and neutropenia.